package com.example.androidtest.utils;

//Copyright 2003-2009 Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland
//www.source-code.biz, www.inventec.ch/chdh
//
//This module is multi-licensed and may be used under the terms
//of any of the following licenses:
//
//EPL, Eclipse Public License, http://www.eclipse.org/legal
//LGPL, GNU Lesser General Public License, http://www.gnu.org/licenses/lgpl.html
//AL, Apache License, http://www.apache.org/licenses
//BSD, BSD License, http://www.opensource.org/licenses/bsd-license.php
//
//Please contact the author if you need another license.
//This module is provided "as is", without warranties of any kind.

/**
* A Base64 Encoder/Decoder.
* 
* <p>
* This class is used to encode and decode data in Base64 format as described in RFC 1521.
* 
* <p>
* Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br>
* Author: Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland<br>
* Multi-licensed: EPL/LGPL/AL/BSD.
* 
* <p>
* Version history:<br>
* 2003-07-22 Christian d'Heureuse (chdh): Module created.<br>
* 2005-08-11 chdh: Lincense changed from GPL to LGPL.<br>
* 2006-11-21 chdh:<br>
* &nbsp; Method encode(String) renamed to encodeString(String).<br>
* &nbsp; Method decode(String) renamed to decodeString(String).<br>
* &nbsp; New method encode(byte[],int) added.<br>
* &nbsp; New method decode(String) added.<br>
* 2009-07-16: Additional licenses (EPL/AL) added.<br>
* 2009-09-16: Additional license (BSD) added.<br>
*/
public class Base64Coder {

//Mapping table from 6-bit nibbles to Base64 characters.
private static char[]    map1 = new char[64];
static {
   int i=0;
   for (char c='A'; c<='Z'; c++) map1[i++] = c;
   for (char c='a'; c<='z'; c++) map1[i++] = c;
   for (char c='0'; c<='9'; c++) map1[i++] = c;
   map1[i++] = '+'; map1[i++] = '/';
  }

//Mapping table from Base64 characters to 6-bit nibbles.
private static byte[]    map2 = new byte[128];
static {
  for (int i=0; i<map2.length; i++) map2[i] = -1;
  for (int i=0; i<64; i++) map2[map1[i]] = (byte)i;
}

/**
 * Encodes a string into Base64 format.
 * No blanks or line breaks are inserted.
 * @param s  a String to be encoded.
 * @return   A String with the Base64 encoded data.
 */
public static String encodeString (String s) {
  return new String(encode(s.getBytes()));
}

/**
 * Encodes a byte array into Base64 format.
 * No blanks or line breaks are inserted.
 * @param in  an array containing the data bytes to be encoded.
 * @return    A character array with the Base64 encoded data.
 */
public static char[] encode (byte[] in) {
  return encode(in,in.length);
}

/**
 * Encodes a byte array into Base64 format.
 * No blanks or line breaks are inserted.
 * @param in   an array containing the data bytes to be encoded.
 * @param iLen number of bytes to process in <code>in</code>.
 * @return     A character array with the Base64 encoded data.
 */
public static char[] encode (byte[] in, int iLen) {
  int oDataLen = (iLen*4+2)/3;       // output length without padding
  int oLen = ((iLen+2)/3)*4;         // output length including padding
  char[] out = new char[oLen];
  int ip = 0;
  int op = 0;
  while (ip < iLen) {
    int i0 = in[ip++] & 0xff;
    int i1 = ip < iLen ? in[ip++] & 0xff : 0;
    int i2 = ip < iLen ? in[ip++] & 0xff : 0;
    int o0 = i0 >>> 2;
    int o1 = ((i0 &   3) << 4) | (i1 >>> 4);
    int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
    int o3 = i2 & 0x3F;
    out[op++] = map1[o0];
    out[op++] = map1[o1];
    out[op] = op < oDataLen ? map1[o2] : '='; op++;
    out[op] = op < oDataLen ? map1[o3] : '='; op++; }
  return out; 
}

/**
 * Decodes a string from Base64 format.
 * @param s  a Base64 String to be decoded.
 * @return   A String containing the decoded data.
 * @throws   IllegalArgumentException if the input is not valid Base64 encoded data.
 */
public static String decodeString (String s) {
  return new String(decode(s)); 
}

/**
 * Decodes a byte array from Base64 format.
 * @param s  a Base64 String to be decoded.
 * @return   An array containing the decoded data bytes.
 * @throws   IllegalArgumentException if the input is not valid Base64 encoded data.
 */
public static byte[] decode (String s) {
  return decode(s.toCharArray()); 
}

/**
 * Decodes a byte array from Base64 format.
 * No blanks or line breaks are allowed within the Base64 encoded data.
 * @param in  a character array containing the Base64 encoded data.
 * @return    An array containing the decoded data bytes.
 * @throws    IllegalArgumentException if the input is not valid Base64 encoded data.
 */
public static byte[] decode (char[] in) {
  int iLen = in.length;
  if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
  while (iLen > 0 && in[iLen-1] == '=') iLen--;
  int oLen = (iLen*3) / 4;
  byte[] out = new byte[oLen];
  int ip = 0;
  int op = 0;
  while (ip < iLen) {
    int i0 = in[ip++];
    int i1 = in[ip++];
    int i2 = ip < iLen ? in[ip++] : 'A';
    int i3 = ip < iLen ? in[ip++] : 'A';
    if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
      throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
    int b0 = map2[i0];
    int b1 = map2[i1];
    int b2 = map2[i2];
    int b3 = map2[i3];
    if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
      throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
    int o0 = ( b0       <<2) | (b1>>>4);
    int o1 = ((b1 & 0xf)<<4) | (b2>>>2);
    int o2 = ((b2 &   3)<<6) |  b3;
    out[op++] = (byte)o0;
    if (op<oLen) out[op++] = (byte)o1;
    if (op<oLen) out[op++] = (byte)o2;
  }
  return out;
}

//Dummy constructor.
private Base64Coder() {}

} // end class Base64Coder
